From the scant knowledge of this culture, a time-worn artwork and a partly restored "map" found within the ruins of his current study, the archaeologist concluded that:

1. the structure of his study had been a 4-tiered 4 x 4 array of rooms.

   (He designated the layout of each tier as:
                A B C D
                E F G H
                I J K L
                M N O P   )

2. in the passage from top to bottom all rooms would be visited just once before moving to a lower level,
   
   and
   
3. the last element in his map (yellow) was clearly the ground floor of this ancient remnant.

"Sir," uttered his assistant displaying a set of diagrams, "I believe these are all possible routes through this structure. While you did insist that a speed challenge may be involved, and two have the least turns, one may be of greater interest."

Eyebrows quizzically raised the archaeologist queried, "And that would be ...?"

"This! 'Four' may have been highly significant to them. This structure is four tiers of 4 by 4 rooms. In this scenario each path has the same number of turns per tier ... and ... that total is divisible by 4!"

Determine, at least, the layout which the assistant most prized.